[Federal Register Volume 87, Number 42 (Thursday, March 3, 2022)]
[Rules and Regulations]
[Pages 11934-11950]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-04374]
=======================================================================
-----------------------------------------------------------------------
NUCLEAR REGULATORY COMMISSION
10 CFR Part 50
[NRC-2017-0025]
RIN 3150-AJ94
Approval of American Society of Mechanical Engineers' Code Cases
AGENCY: Nuclear Regulatory Commission.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is amending its
regulations to incorporate by reference revisions of three regulatory
guides to approve new, revised, and reaffirmed code cases published by
the American Society of Mechanical Engineers. The NRC is also
incorporating by reference one NRC NUREG associated with a condition on
one of the regulatory guides. This action allows nuclear power plant
licensees and applicants for construction permits, operating licenses,
combined licenses, standard design certifications, standard design
approvals, and manufacturing licenses to use the code cases listed in
these regulatory guides as voluntary alternatives to engineering
standards for the construction, inservice inspection, and inservice
testing of nuclear power plant components. These engineering standards
are set forth in the American Society of Mechanical Engineers' Boiler
and Pressure Vessel Codes and American Society of Mechanical Engineers'
Operation and Maintenance Codes, which are currently incorporated by
reference into the NRC's regulations. Further, this final rule
announces the availability of a related regulatory guide, not
incorporated by reference into the NRC's regulations, that lists code
cases that the NRC has not approved for use.
DATES: This final rule is effective on April 4, 2022. The incorporation
by reference of certain publications listed in the regulation is
approved by the Director of the Federal Register as of April 4, 2022.
ADDRESSES: Please refer to Docket ID NRC-2017-0025 when contacting the
NRC about the availability of information for this action. You may
obtain publicly-available information related to this action by any of
the following methods:
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2017-0025. Address
questions about NRC dockets to Dawn Forder; telephone: 301-415-3407;
email: [email protected]. For technical questions, contact the
individuals listed in the FOR FURTHER INFORMATION CONTACT section of
this document.
NRC's Agencywide Documents Access and Management System
(ADAMS): You may obtain publicly-available documents online in the
ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``Begin Web-based ADAMS
Search.'' For problems with ADAMS, please contact the NRC's Public
Document Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or
by email to [email protected]. For the convenience of the reader,
instructions about obtaining materials referenced in this document are
provided in the ``Availability of Documents'' section.
NRC's PDR: You may examine and purchase copies of public
documents, by appointment, at the NRC's PDR, Room P1 B35, One White
Flint North, 11555 Rockville Pike, Rockville, Maryland 20852. To make
an appointment to visit the PDR, please send an email to
[email protected] or call 1-800-397-4209 or 301-415-4737, between
8:00 a.m. and 4:00 p.m. (ET), Monday through Friday, except Federal
holidays.
Technical Library: The Technical Library, which is located
at Two White Flint North, 11545 Rockville Pike, Rockville, Maryland
20852, is open by appointment only. Interested parties may make
appointments to examine documents by contacting the NRC Technical
Library by email at [email protected] between 8:00 a.m. and 4:00
p.m. (ET), Monday through Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Martha Barillas, Office of Nuclear
Material Safety and Safeguards; telephone: 301-415-2760, email:
[email protected]; or Bruce Lin, Office of Nuclear Regulatory
Research, telephone: 301-415-2446; email: [email protected]. Both are
staff of the U.S. Nuclear Regulatory Commission, Washington, DC 20555-
0001.
SUPPLEMENTARY INFORMATION:
Executive Summary
A. Need for the Regulatory Action
The purpose of this regulatory action is to incorporate by
reference into the NRC's regulations the latest revisions of three
regulatory guides (RGs). This regulatory action is also incorporating
by reference, NUREG-2228, ``Weld Residual Stress Finite Element
Analysis Validation: Part II--Proposed Validation Procedure,'' that is
associated with a condition in one of the regulatory guides. The three
RGs identify new,
[[Page 11935]]
revised, and reaffirmed code cases published by the American Society of
Mechanical Engineers (ASME), which the NRC has determined are
acceptable for use as voluntary alternatives to compliance with certain
provisions of the ASME Boiler and Pressure Vessel Code (BPV Code) and
the ASME Code for Operation and Maintenance of Nuclear Power Plants,
Division 1, OM Code: Section IST (OM Code), currently incorporated by
reference into the NRC's regulations.
B. Major Provisions
The three RGs that the NRC is incorporating by reference are RG
1.84, ``Design, Fabrication, and Materials Code Case Acceptability,
ASME Section III,'' Revision 39; RG 1.147, ``Inservice Inspection Code
Case Acceptability, ASME Section XI, Division 1,'' Revision 20; and RG
1.192, ``Operation and Maintenance [OM] Code Case Acceptability, ASME
OM Code,'' Revision 4. The NRC is also incorporating by reference
NUREG-2228, which provides the procedure for validating the weld
residual stress analysis methodology associated with ASME Code Case N-
847. This final rule allows nuclear power plant licensees and
applicants for construction permits, operating licenses, combined
licenses, standard design certifications, standard design approvals,
and manufacturing licenses to use the code cases newly listed in these
revised RGs as voluntary alternatives to engineering standards for the
construction, inservice inspections, and inservice testing of nuclear
power plant components. In this document, the NRC also notifies the
public of the availability of RG 1.193, ``ASME Code Cases Not Approved
for Use,'' Revision 7. This document lists code cases that the NRC has
not approved for generic use and is not incorporated by reference into
the NRC's regulations.
The NRC prepared a regulatory analysis to determine the expected
quantitative costs and benefits of this final rule, as well as
qualitative factors to be considered in the NRC's rulemaking decision.
The analysis concluded that this rule results in net savings to the
industry and the NRC. As shown in Table 1, the estimated total net
benefits relative to the regulatory baseline range from approximately
$5.86 million (7-percent net present value) to $6.67 million (3-percent
net present value).
Table 1--Cost Benefit Summary
----------------------------------------------------------------------------------------------------------------
Total averted costs (costs)
-----------------------------------------------
Attribute 7% Net present 3% Net present
Undiscounted value value
----------------------------------------------------------------------------------------------------------------
Industry Implementation......................................... $0 $0 $0
Industry Operation.............................................. 4,920,000 3,920,000 4,450,000
-----------------------------------------------
Total Industry Costs........................................ 4,920,000 3,920,000 4,450,000
NRC Implementation.............................................. 0 0 0
NRC Operation................................................... 2,460,000 1,940,000 2,220,000
-----------------------------------------------
Total NRC Costs............................................. 2,460,000 1,940,000 2,220,000
-----------------------------------------------
Net..................................................... 7,380,000 5,860,000 6,670,000
----------------------------------------------------------------------------------------------------------------
The regulatory analysis also considered the following qualitative
considerations: (1) Flexibility and decreased uncertainty for licensees
when making modifications or preparing to perform inservice inspection
or inservice testing; (2) consistency with the provisions of the
National Technology Transfer and Advancement Act of 1995, which
encourages Federal regulatory agencies to consider adopting voluntary
consensus standards as an alternative to de novo agency development of
standards affecting an industry; (3) consistency with the NRC's policy
of evaluating the latest versions of consensus standards in terms of
their suitability for endorsement by regulations and regulatory guides;
and (4) consistency with the NRC's goal to harmonize with international
standards to improve regulatory efficiency for both the NRC and
international standards groups.
The regulatory analysis concludes that this final rule should be
adopted because it is justified when integrating the cost-beneficial
quantitative results and the positive and supporting nonquantitative
considerations in the decision. For more information, please see the
final regulatory analysis as indicated in Section XVI, ``Availability
of Documents,'' of this document.
Table of Contents
I. Background
II. Discussion
III. Opportunities for Public Participation
IV. Public Comment Analysis
V. Section-by-Section Analysis
VI. Regulatory Flexibility Certification
VII. Regulatory Analysis
VIII. Backfitting and Issue Finality
IX. Plain Writing
X. Environmental Assessment and Final Finding of No Significant
Environmental Impact
XI. Paperwork Reduction Act
XII. Congressional Review Act
XIII. Voluntary Consensus Standards
XIV. Incorporation by Reference-Reasonable Availability to
Interested Parties
XV. Availability of Guidance
XVI. Availability of Documents
I. Background
The ASME develops and publishes the ASME BPV Code, which contains
requirements for the design, construction, and inservice inspection
examination of nuclear power plant components, and the ASME OM Code,\1\
which contains requirements for inservice testing of nuclear power
plant components. In response to BPV and OM Code user requests, the
ASME develops code cases that provide voluntary alternatives to BPV and
OM Code requirements under special circumstances.
---------------------------------------------------------------------------
\1\ The editions and addenda of the ASME Code for Operation and
Maintenance of Nuclear Power Plants have had different titles from
2005 to 2017 and are referred to as the ``OM Code'' collectively in
this rule.
---------------------------------------------------------------------------
The NRC approves the ASME BPV and OM Codes in Sec. 50.55a, ``Codes
and standards,'' of title 10 of the Code of Federal Regulations (10
CFR) through the process of incorporation by reference. As such, each
provision of the ASME Codes incorporated by reference into and mandated
by Sec. 50.55a
[[Page 11936]]
constitutes a legally-binding NRC requirement imposed by rule. As noted
previously, the ASME code cases, for the most part, represent
alternative approaches for complying with provisions of the ASME BPV
and OM Codes. Accordingly, the NRC periodically amends Sec. 50.55a to
incorporate by reference the NRC's RGs listing approved ASME code cases
that may be used as voluntary alternatives to the BPV and OM Codes.\2\
---------------------------------------------------------------------------
\2\ See Federal Register final rule, ``Incorporation by
Reference of ASME BPV and OM Code Cases'' (68 FR 40469; July 8,
2003).
---------------------------------------------------------------------------
This final rule is the latest in a series of rules that incorporate
by reference new versions of several RGs identifying new, revised, and
reaffirmed,\3\ and unconditionally or conditionally acceptable ASME
code cases that the NRC approves for use. In developing these RGs, the
NRC reviews the ASME BPV and OM code cases, determines the
acceptability of each code case, and publishes its findings in the RGs.
The RGs are revised periodically as new code cases are published by the
ASME. The NRC incorporates by reference the RGs listing acceptable and
conditionally acceptable ASME code cases into Sec. 50.55a. The NRC
published a final rule dated March 16, 2020, that incorporated by
reference into Sec. 50.55a the most recent versions of the RGs, which
are RG 1.84, ``Design, Fabrication, and Materials Code Case
Acceptability, ASME Section III,'' Revision 38; RG 1.147, ``Inservice
Inspection Code Case Acceptability, ASME Section XI, Division 1,''
Revision 19; and RG 1.192, ``Operation and Maintenance Code Case
Acceptability, ASME OM Code,'' Revision 3.
---------------------------------------------------------------------------
\3\ Code Cases are categorized by the ASME as one of three
types: New, revised, or reaffirmed. A new Code Case provides for a
new alternative to specific the ASME Code provisions or addresses a
new need. The ASME defines a revised Code Case to be a revision
(modification) to an existing Code Case to address, for example,
technological advancements in examination techniques or to address
NRC conditions imposed in one of the RGs that have been incorporated
by reference into Sec. 50.55a. The ASME defines ``reaffirmed'' as
an OM Code Case that does not have any change to technical content,
but includes editorial changes.
---------------------------------------------------------------------------
II. Discussion
This final rule incorporates by reference NUREG-2228 and the latest
revisions of the NRC's RGs that list the ASME BPV and OM code cases
that the NRC finds to be acceptable, or acceptable with NRC-specified
conditions (``conditionally acceptable''). Regulatory Guide 1.84,
Revision 39, supersedes the incorporation by reference of Revision 38;
RG 1.147, Revision 20, supersedes the incorporation by reference of
Revision 19; and RG 1.192, Revision 4, supersedes the incorporation by
reference of Revision 3.
The ASME code cases that are the subject of this final rule are the
new and revised Section III and Section XI code cases as listed in
Supplements 0 through 7 to the 2015 Edition of the ASME BPV Code,
Supplements 0 through 7 to the 2017 Edition of the ASME BPV Code,
Supplements 0 and 1 to the 2019 Edition of the ASME BPV Code, and the
OM code cases listed in the 2020 Edition of the ASME OM Code and on the
ASME Codes & Standards (C&S) Connect website.\4\
---------------------------------------------------------------------------
\4\ The ASME included code cases with the published editions and
addenda of the OM Code through the 2017 Edition. Starting with the
2020 Edition, code cases were not published with the OM Code; an
applicability index for ASME OM code cases was published. Code cases
are available on the ASME website under the ``O&M CASES'' tab in the
left-hand column at https://go.asme.org/OMcommittee.
---------------------------------------------------------------------------
The latest editions and addenda of the ASME BPV and OM Codes that
the NRC has approved for use are referenced in Sec. 50.55a. The ASME
also publishes code cases that provide alternatives to existing Code
requirements that the ASME developed and approved. This final rule
incorporates by reference the most recent revisions of RGs 1.84, 1.147,
and 1.192, which allow nuclear power plant licensees, and applicants
for combined licenses, standard design certifications, standard design
approvals, and manufacturing licenses under the regulations that govern
license certifications, to use the code cases listed in these RGs as
suitable alternatives to the ASME BPV and OM Codes for the
construction, inservice inspections, and inservice testing of nuclear
power plant components. Because the NRC is requiring the use of NUREG-
2228 within a condition on Code Case N-847, the NRC is also
incorporating by reference NUREG-2228. The ASME publishes the OM Code
Cases and lists the code cases in the ASME OM Code edition and on the
ASME C&S Connect website. In contrast, the ASME publishes BPV code
cases in a separate document and at a different time than the ASME BPV
code editions. This final rule identifies the code cases by the edition
of the ASME BPV Code or ASME OM Code under which they were published by
the ASME.
The following general guidance applies to the use of the ASME code
cases approved in the latest versions of the RGs that are incorporated
by reference into Sec. 50.55a as part of this final rule.
Specifically, the use of the code cases listed in the latest versions
of RGs 1.84, 1.147, and 1.192 are acceptable with the specified
conditions when implementing the editions and addenda of the ASME BPV
and OM Codes incorporated by reference in Sec. 50.55a.
The approval of a code case in the NRC's RGs constitutes acceptance
of its technical position for applications that are not precluded by
regulatory or other requirements or by the recommendations in these
RGs. The applicant or licensee is responsible for ensuring that use of
the code case does not conflict with regulatory requirements or
licensee commitments. The code cases listed in the RGs are acceptable
for use within the limits specified in the code cases. If the RG states
an NRC condition on the use of a code case, then the NRC condition
supplements and does not supersede any condition(s) specified in the
code case, unless otherwise stated in the NRC condition.
The ASME code cases may be revised for many reasons (e.g., to
incorporate operational examination and testing experience and to
update material requirements based on research results). On occasion,
an inaccuracy in an equation is discovered or an examination, as
practiced, is found not to be adequate to detect a newly discovered
degradation mechanism.
Therefore, when an applicant or a licensee initially implements a
code case, Sec. 50.55a requires that the applicant or the licensee
implement the most recent version of that code case, as listed in the
RGs incorporated by reference. Code cases superseded by revision are no
longer acceptable for new applications unless otherwise indicated.
Section III of the ASME BPV Code applies to new construction (i.e.,
the edition and addenda to be used in the construction of a plant are
selected based on the date of the construction permit and are not
changed thereafter, except voluntarily by the applicant or the
licensee). Hence, if a Section III code case is implemented by an
applicant or a licensee and a later version of the code case is
incorporated by reference into Sec. 50.55a and listed in the RG, the
applicant or licensee may use either version of the code case (subject,
however, to whatever change requirements apply to its licensing basis
(e.g., Sec. 50.59)).
A licensee's inservice inspection and inservice testing programs
must be updated every 10 years to the latest edition and addenda of the
ASME BPV Code, Section XI, and the OM Code, respectively, that were
incorporated by reference into Sec. 50.55a and in effect 18
[[Page 11937]]
months prior to the start of the next inspection and testing interval.
Licensees that were using a code case prior to the effective date of
its revision may continue to use the previous version for the remainder
of the 120-month inservice inspection or inservice testing interval.
This relieves licensees of the burden of having to update their
inservice inspection or inservice testing program each time a code case
is revised by the ASME and approved for use by the NRC. Code cases
apply to specific editions and addenda, and code cases may be revised
if they are no longer accurate or adequate, so licensees choosing to
continue using a code case during the subsequent inservice inspection
or inservice testing interval must implement the latest version
incorporated by reference into Sec. 50.55a and listed in the RGs.
The ASME may annul code cases that are no longer required, are
determined to be inaccurate or inadequate, or have been incorporated
into the BPV or OM Codes. A code case may be revised, for example, to
incorporate user experience. The older or superseded version of the
code case cannot be applied by the licensee or applicant unless it was
applied prior to being annulled or superseded.
If an applicant or a licensee applied a code case before it was
listed as superseded, the applicant or the licensee may continue to
use the code case until the applicant or the licensee updates its
construction Code of Record (in the case of an applicant, updates
its application) or until the licensee's 120-month inservice
inspection or inservice testing update interval expires, after which
the continued use of the code case is prohibited unless NRC
authorization is given under Sec. 50.55a(z). If a code case is
incorporated by reference into Sec. 50.55a and later a revised
version is issued by the ASME because experience has shown that the
design analysis, construction method, examination method, or testing
method is inadequate, the NRC will amend Sec. 50.55a and the
relevant RG to remove the approval of the superseded code case.
Applicants and licensees should not begin to implement such
superseded code cases in advance of the rulemaking.
A. ASME Code Cases Approved for Unconditional Use
The code cases discussed in Table I are new, revised, or reaffirmed
code cases in which the NRC approves for use without conditions. The
table identifies the regulatory guide listing the applicable code case
that the NRC approves for use.
Table I--Acceptable Code Cases
----------------------------------------------------------------------------------------------------------------
Code Case No. Published with supplement Title
----------------------------------------------------------------------------------------------------------------
Boiler and Pressure Vessel Code Section III
(Addressed in RG 1.84, Table 1)
----------------------------------------------------------------------------------------------------------------
N-249-17.............................. 0 (2019 Edition)........................ Additional Materials for
Subsection NF, Classes 1, 2,
3, and MC Supports Fabricated
without Welding, Section III,
Division 1.
N-539-1............................... 0 (2017 Edition)........................ UNS N08367 in Class 2 and 3
Valves, Section III, Division
1.
N-692-1............................... 6 (2015 Edition)........................ Use of Standard Welding
Procedures, Section III,
Division 1.
N-721-1............................... 5 (2017 Edition)........................ Alternative Rules for Linear
Piping Supports, Section III,
Division 1.
N-801-3............................... 1 (2017 Edition)........................ Rules for Repair of N-Stamped
Class 1, 2, and 3 Components,
Section III, Division 1.
N-822-4............................... 7 (2015 Edition)........................ Application of the ASME
Certification Mark, Section
III, Divisions 1, 2, 3, and
5.
N-855................................. 2 (2015 Edition)........................ SB-148 C95800 Valves for Class
3 Construction, Section III,
Division 1.
N-856................................. 2 (2015 Edition)........................ SA-494 Grade CW-12MW (UNS
N30002) Nickel Alloy Castings
for Construction of NPS 2\1/
2\ and Smaller Flanged Valves
for Class 3 Construction,
Section III, Division 1.
N-859................................. 5 (2015 Edition)........................ Construction of ASME B16.9
Wrought Buttwelding Fittings
and ASME B16.11 Forged
Fittings Made From SB-366 UNS
N04400 Material for Section
III, Class 3 Construction,
Section III, Division 1.
N-863-1............................... 1 (2017 Edition)........................ Post Weld Heat Treatment
(PWHT) of Valve Seal Welds
for P4 and P5A Materials,
Section III, Division 1.
N-866................................. 0 (2017 Edition)........................ Alternative Materials for
Construction of Section III,
Class 2 Vessels, Section III,
Division 1.
N-870-1............................... 4 (2017 Edition)........................ Rules for the Elimination of
External Surface Defects on
Class 1, 2, and 3 Piping,
Pumps, or Valves After
Component Stamping and Prior
to Completion of the N-3 Data
Report, Section III, Division
1.
N-879................................. 1 (2017 Edition)........................ Use of Micro-Alloyed Carbon
Steel Bar in Patented
Mechanical Joints and
Fittings, Classes 1, 2, and
3, Section III, Division 1.
N-884................................. 0 (2019 Edition)........................ Procedure to Determine Strain
Rate for Use with the
Environmental Fatigue Design
Curve Method and the
Environmental Fatigue
Correction Factor, Fen,
Method as Part of an
Environmental Fatigue
Evaluation for Components
Analyzed per the NB-3200
Rules, Section III, Division
1.
N-887................................. 6 (with errata issued in 3/19E)......... Alternatives to the
Requirements of NB-4424.2(a),
Figure NB-4250-2, and Figure
NB-4250-3, Section III,
Division 1.
N-891................................. 0 (2019 Edition)........................ Alternative Requirements to
Appendix XXVI, XXVI-2400,
XXVI-4130, and XXVI-4131 for
Inspection and Repair of
Indentations for Polyethylene
Pipe and Piping Components,
Section III, Division 1.
----------------------------------------------------------------------------------------------------------------
Boiler and Pressure Vessel Code Section XI
(Addressed in RG 1.147, Table 1)
----------------------------------------------------------------------------------------------------------------
N-561-3............................... 0 (2019 Edition)........................ Alternative Requirements for
Wall Thickness Restoration of
Class 2 and High Energy Class
3 Carbon Steel Piping,
Section XI, Division 1.
N-638-10.............................. 1 (2019 Edition)........................ Similar and Dissimilar Metal
Welding Using Ambient
Temperature Machine GTAW
Temper Bead Technique,
Section XI, Division 1.
N-653-2............................... 2 (2015 Edition)........................ Qualification Requirements for
Full Structural Overlaid
Wrought Austenitic Piping
Welds, Section XI, Division
1.
N-702-1............................... 1 (2019 Edition)........................ Alternative Requirements for
Boiling Water Reactor (BWR)
Nozzle Inner Radius and
Nozzle-to-Shell Welds,
Section XI, Division 1.
N-716-2............................... 0 (2017 Edition)........................ Alternative Piping
Classification and
Examination Requirements,
Section XI, Division 1.
[[Page 11938]]
N-768................................. 0 (2019 Edition)........................ Alternative Volumetric
Coverage Requirements for
Ultrasonic Examination of
Class 1 and 2 Pressure Vessel
Weld Joints Greater Than 2
in. (50 mm) in Thickness,
Section XI, Division 1.
N-786-3............................... 1 (2017 Edition)........................ Alternative Requirements for
Sleeve Reinforcement of Class
2 and 3 Moderate Energy
Carbon Steel Piping, Section
XI, Division 1.
N-789-3............................... 1 (2017 Edition)........................ Alternative Requirements for
Pad Reinforcement of Class 2
and 3 Moderate Energy Carbon
Steel Piping for Raw Water
Service, Section XI, Division
1.
N-809................................. 2 (2015 Edition)........................ Reference Fatigue Crack Growth
Rate Curves for Austenitic
Stainless Steels in
Pressurized Reactor Water
Environments, Section XI,
Division 1.
N-845-1............................... 6 (2015 Edition)........................ Qualification Requirements for
Bolts and Studs, Section XI,
Division 1.
N-848-1............................... 0 (2017 Edition)........................ Alternative Characterization
Rules for Quasi-Laminar
Flaws, Section XI, Division
1.
N-851................................. 0 (2015 Edition)........................ Alternate Method for
Establishing the Reference
Temperature for Pressure
Retaining Materials, Section
XI, Division 1.
N-858................................. 2 (2017 Edition)........................ Alternative Volumetric
Coverage Requirements for
Ultrasonic Examination of
Class 1 Nozzle-to-Vessel
Welds, Section XI, Division
1.
N-865................................. 2 (2017 Edition)........................ Alternative Requirements for
Pad Reinforcement of Class 2
and 3 Atmospheric Storage
Tanks, Section XI, Division
1.
N-867................................. 0 (2017 Edition)........................ Clarification of NDE Practical
Examination Requirements,
Section XI, Division 1.
N-873................................. 1 (2017 Edition)........................ Examination Requirements for
the Core Makeup Tanks,
Section XI, Division 1.
N-874................................. 7 (2017 Edition)........................ Temporary Acceptance of
Leakage Through Brazed Joints
of Class 3 Copper, Copper-
Nickel, and Nickel-Copper
Moderate Energy Piping,
Section XI, Division 1.
N-877................................. 2 (2017 Edition)........................ Alternative Characterization
Rules for Multiple Subsurface
Radially Oriented Planar
Flaws, Section XI, Division
1.
N-882................................. 6 (2017 Edition)........................ Alternative Requirements for
Attaching Nonstructural
Electrical Connections to
Class 2 and 3 Components,
Section XI, Division 1.
N-885................................. 0 (2019 Edition)........................ Alternative Requirements for
Table IWB-2500-1, Examination
Category B-N-1, Interior of
Reactor Vessel, Category B-N-
2, Welded Core Support
Structures and Interior
Attachments to Reactor
Vessels, Category B-N-3,
Removable Core Support
Structures, Section XI,
Division 1.
N-892................................. 0 (2019 Edition)........................ Alternative Requirement for
Form OAR-1, Owner's Activity
Report, Completion Time,
Section XI, Division 1.
----------------------------------------------------------------------------------------------------------------
Operation and Maintenance Code
(Addressed in RG 1.192, Table 1)
----------------------------------------------------------------------------------------------------------------
OMN-13, Revision 3.................... 2020 Edition............................ Performance-Based Requirements
for Extending Snubber
Inservice Visual Examination
Interval at LWR Power Plants.
OMN-15, Revision 3.................... 2020 Edition............................ Performance-Based Requirements
for Extending the Snubber
Operational Readiness Testing
Interval at LWR Power Plants.
OMN-17, Revision 1.................... 2020 Edition............................ Alternative Requirements for
Testing ASME Class 1 Pressure
Relief/Safety Valves.
OMN-18 \5\............................ 2020 Edition............................ Alternate Testing Requirements
for Pumps Tested Quarterly
Within 20% of
Design Flow.
OMN-22................................ 2020 Edition............................ Smooth Running Pumps.
OMN-23................................ 2020 Edition............................ Alternative Requirements for
Testing Pressure Isolation
Valves.
OMN-24................................ 2020 Edition............................ Alternative Requirements for
Testing ASME Class 2 and 3
Pressure Relief Valves (For
Relief Valves in a Group of
One).
OMN-25................................ 2020 Edition............................ Alternative Requirements for
Testing Appendix I Pressure
Relief Valves.
OMN-26................................ 2020 Edition............................ Alternate Risk-Informed and
Margin Based Rules for
Inservice Testing of Motor
Operated Valves.
OMN-27................................ 2020 Edition............................ Alternative Requirements for
Testing Category A Valves
(Non-PIV/CIV)
----------------------------------------------------------------------------------------------------------------
---------------------------------------------------------------------------
\5\ As a result of a public comment, the NRC agreed that the
condition to require the slightly more restrictive upper-end values
of the acceptable ranges for flow and differential pressure are not
necessary to provide reasonable assurance that the implementation of
Code Case OMN-18 will demonstrate the acceptable performance of
pumps within the scope of the ASME OM Code. Therefore, the NRC
deleted the condition proposed and moved OMN-18 to Table I.
---------------------------------------------------------------------------
B. ASME Code Cases Approved for Use With Conditions
The NRC determined that certain code cases, as issued by the ASME,
are generally acceptable for use, but that the alternative requirements
specified in those code cases must be supplemented in order to provide
an acceptable level of quality and safety. Accordingly, the NRC imposes
conditions on the use of these code cases to modify, limit, or clarify
their requirements. The conditions specify, for each applicable code
case, the additional activities that must be performed, the limits on
the activities specified in the code case, and/or the supplemental
information needed to provide clarity. These ASME code cases, listed in
Table II below, are included in Table 2 of RG 1.84, RG 1.147, and RG
1.192. This section provides the NRC's evaluation of the code cases and
the reasons for the NRC's conditions. Notations indicate the conditions
duplicated from previous versions of the RG.
[[Page 11939]]
Table II--Conditionally Acceptable Code Cases
----------------------------------------------------------------------------------------------------------------
Code Case No. Published with supplement Title
----------------------------------------------------------------------------------------------------------------
Boiler and Pressure Vessel Code Section III
(Addressed in RG 1.84, Table 2)
----------------------------------------------------------------------------------------------------------------
N-71-20............................... 6 (2015 Edition)........................ Additional Materials for
Subsection NF, Class 1, 2, 3,
and MC Supports Fabricated by
Welding, Section III,
Division 1.
N-155-3............................... 5 (2015 Edition)........................ Fiberglass Reinforced
Thermosetting Resin Pipe,
Section III, Division 1.
N-755-4............................... 1 (2017 Edition)........................ Use of Polyethylene (PE) Class
3 Plastic Pipe, Section III,
Division 1.
N-779................................. 8 (2007 Edition) \6\.................... Alternative Rules for
Simplified Elastic-Plastic
Analysis Class 1, Section
III, Division 1.
N-852................................. 0 (2015 Edition)........................ Application of the ASME NPT
Stamp, Section III, Divisions
1, 2, 3, and 5.
N-883................................. 5 (2017 Edition)........................ Construction of Items Prior to
the Establishment of a
Section III, Division 1
Owner, Section III, Division
1.
N-886................................. 6 (2017 Edition)........................ Use of Polyethylene Pipe for
Class 3, Section III,
Division 1.
----------------------------------------------------------------------------------------------------------------
Boiler and Pressure Vessel Code Section XI
(Addressed in RG 1.147, Table 2)
----------------------------------------------------------------------------------------------------------------
N-513-5............................... 6 (2017 Edition)........................ Evaluation Criteria for
Temporary Acceptance of Flaws
in Moderate Energy Class 2 or
3 Piping and Gate Valves,
Section XI, Division 1.
N-516-5............................... 6 (2015 Edition)........................ Underwater Welding, Section
XI, Division 1.
N-597-3............................... 5 (2013 Edition)........................ Evaluation of Pipe Wall
Thinning, Section XI.
N-705-1............................... 2 (2017 Edition)........................ Evaluation Criteria for
Temporary Acceptance of
Degradation in Moderate
Energy Class 2 or 3 Vessels
and Tanks, Section XI,
Division 1.
N-766-3............................... 2 (2017 Edition)........................ Nickel Alloy Reactor Coolant
Inlay and Onlay for
Mitigation of PWR Full
Penetration Circumferential
Nickel Alloy Dissimilar Metal
Welds in Class 1 Items,
Section XI, Division 1.
N-778................................. 0 (2010 Edition)........................ Alternative Requirements for
Preparation and Submittal of
Inservice Inspection Plans,
Schedules, and Preservice and
Inservice Inspection Summary
Reports, Section XI, Division
1.
N-831-1............................... 7 (2017 Edition)........................ Ultrasonic Examination in Lieu
of Radiography for Welds in
Ferritic or Austenitic Pipe,
Section XI, Division 1.
N-847................................. 0 (2017 Edition)........................ Partial Excavation and
Deposition of Weld Metal for
Mitigation of Class 1 Items,
Section XI, Division 1.
N-864................................. 2 (2017 Edition)........................ Reactor Vessel Threads in
Flange Examinations, Section
XI, Division 1.
N-869................................. 6 (2017 Edition)........................ Evaluation Criteria for
Temporary Acceptance of Flaws
in Class 2 or 3 Piping,
Section XI, Division 1.
N-876................................. 2 (2017 Edition)........................ Austenitic Stainless Steel
Cladding and Nickel Base
Cladding Using Ambient
Temperature Automatic or
Machine Dry Underwater Laser
Beam Welding (ULBW) Temper
Bead Technique, Section XI,
Division 1.
N-878................................. 1 (2017 Edition)........................ Alternative to QA Program
Requirements of IWA-4142,
Section XI, Division 1.
N-880................................. 2 (2017 Edition)........................ Alternative to Procurement
Requirements of IWA-4143 for
Small Nonstandard Welded
Fittings, Section XI,
Division 1.
N-889................................. 7 (2017 Edition)........................ Reference Stress Corrosion
Crack Growth Rate Curves for
Irradiated Austenitic
Stainless Steel in Light-
Water Reactor Environments,
Section XI, Division 1.
N-890................................. 0 (2019 Edition)........................ Materials Exempted From G-
2110(b) Requirement, Section
XI, Division 1.
----------------------------------------------------------------------------------------------------------------
Operation and Maintenance Code
(Addressed in RG 1.192, Table 2)
----------------------------------------------------------------------------------------------------------------
OMN-1, Revision 2..................... 2020 Edition............................ Alternative Rules for
Preservice and Inservice
Testing of Active Electric
Motor-Operated Valve
Assemblies in Light-Water
Reactor Power Plants.
OMN-3................................. 2020 Edition............................ Requirements for Safety
Significance Categorization
of Components Using Risk
Insights for Inservice
Testing of LWR Power Plants.
OMN-4................................. 2020 Edition............................ Requirements for Risk Insights
for Inservice Testing of
Check Valves at LWR Power
Plants.
OMN-9................................. 2020 Edition............................ Use of a Pump Curve for
Testing.
OMN-12................................ 2020 Edition............................ Alternative Requirements for
Inservice Testing Using Risk
Insights for Pneumatically
and Hydraulically Operated
Valve Assemblies in Light-
Water Reactor Power Plants
(OM-Code 1998, Subsection
ISTC).
OMN-19................................ 2020 Edition............................ Alternative Upper Limit for
the Comprehensive Pump Test.
OMN-20................................ 2020 Edition............................ Inservice Test Frequency.
----------------------------------------------------------------------------------------------------------------
---------------------------------------------------------------------------
\6\ Correcting editorial error from proposed rule to final rule
to state correct supplement 8.
---------------------------------------------------------------------------
1. ASME BPV Code, Section III Code Cases (RG 1.84)
Code Case N-71-20 [Supplement 6, 2015 Edition]
Type: Revised.
Title: Additional Materials for Subsection NF, Class 1, 2, 3, and
MC Supports Fabricated by Welding, Section III, Division 1.
The conditions on Code Case N-71-20 are the same as the conditions
on N-71-19 that were approved by the NRC in Revision 38 of RG 1.84.
When the ASME revised N-71, the code case was not modified in a way
that would make
[[Page 11940]]
it possible for the NRC to remove the conditions. Therefore, the
conditions are retained in Revision 39 of RG 1.84.
Code Case N-155-3 [Supplement 5, 2015 Edition]
Type: Revised.
Title: Fiberglass Reinforced Thermosetting Resin Pipe, Section III,
Division 1.
The conditions on Code Case N-155-3 are the same as the conditions
on N-155-2 that were approved by the NRC in Revision 38 of RG 1.84.
When the ASME revised N-155-2, the code case was not modified in a way
that would make it possible for the NRC to remove the conditions.
Therefore, the conditions are retained in Revision 39 of RG 1.84.
Code Case N-755-4 [Supplement 1, 2017 Edition]
Type: Revised.
Title: Use of Polyethylene (PE) Class 3 Plastic Pipe, Section III,
Division 1.
This code case is applicable only to butt fusion joints and the
content was incorporated into Mandatory Appendix XXVI in the 2015
Edition of Section III of the ASME Code. The relevant provisions of
Code Case N-755-4 are the same as those in Mandatory Appendix XXVI.
Therefore, the NRC is applying the same conditions to Code Case N-755-
4. The NRC has determined that these conditions are necessary to ensure
structural integrity of the polyethylene piping and fusion joints when
the polyethylene piping is used in Class 3 safety-related applications.
Code Case N-779 [Supplement 8, 2007 Edition]
Type: New.
Title: Alternative Rules for Simplified Elastic-Plastic Analysis
Class 1, Section III, Division 1.
The NRC finds the code case satisfactory and technically acceptable
for use only with code editions Summer 1979 and later. This code case,
as written, is not acceptable for use with editions of Section III
earlier than the Summer 1979 Edition, which included the term Delta T1
in NB-3600 Equation 10, because the code case is based on equations
used in the Summer 1979 Edition and later editions of the Code.
Code Case N-852 [Supplement 0, 2015 Edition]
Type: New.
Title: Application of the ASME NPT Stamp, Section III, Divisions 1,
2, 3, and 5.
The NRC approved this code case with a condition in a Sec. 50.55a
rulemaking issued in 2017 (82 FR 32934; July 18, 2017), and the
supplement was not modified in a way that would make it possible for
the NRC to remove the condition. Therefore, the condition is retained
in Revision 39 of RG 1.84.
Code Case N-883 [Supplement 5, 2017 Edition]
Type: New.
Title: Construction of Items Prior to the Establishment of a
Section III, Division 1 Owner, Section III, Division 1.
This code case allows certificate holders to construct all items
prior to the establishment of an Owner. Code Case N-883 was developed
to address international stakeholders and identify the ASME as a global
standard development organization. The NRC's main concern is that
without the designation of an Owner, the NRC would not be able to
provide regulatory oversight of the ASME certificate holder
manufacturing the items, which is not consistent with appendix B to 10
CFR part 50 and the requirements in Sec. 50.55(a) for a basic
component. During discussions with the ASME staff on this code case, it
was determined that the NRC would condition this code case based on
regulatory oversight, as would other regulatory bodies depending on
each countries' specific regulations. This is evident as this code case
specifies that the ``the items have been constructed by [ASME]
Certificate Holders who are specifically authorized by the Regulatory
Authority having jurisdiction over the Owner's facility to construct
items using this Case.'' The condition, ``This Code Case may be used
for the construction of items by a holder of a construction permit,
operating license, or combined license under 10 CFR part 50 or part
52,'' provides this specific regulatory authorization thereby ensuring
the appropriate regulatory oversight. As a result of public comment,
the NRC clarified the condition on the code case as follows: ``This
Code Case may only be used for the construction of items by a holder of
a construction permit, operating license, or combined license under 10
CFR part 50 or 10 CFR part 52. This Code Case may not be used by a
holder of a manufacturing license or standard design approval or by a
design certification applicant.''
Code Case N-886 [Supplement 6, 2017 Edition]
Type: New.
Title: Use of Polyethylene Pipe for Class 3, Section III, Division
1.
This code case is applicable for the use of polyethylene pipe in
Section III, Class 3, Division 1 above ground applications. This code
case refers to Mandatory Appendix XXVI of Section III of the ASME Code.
The 2015 Edition of Appendix XXVI contains requirements for butt fusion
joints for buried piping. The 2017 Edition of Appendix XXVI contains
requirements for butt fusion and electrofusion joints for buried
piping. Therefore, all the conditions as noted in Section III of the
2015-2017 Code Edition rule related to buried piping Mandatory Appendix
XXVI apply to this code case. The same conditions as buried piping also
apply to above ground application. One additional condition is needed
for above ground applications related to fire protection. A condition
on fire protection is needed because polyethylene material is
combustible and above ground uses are more susceptible to fire hazards.
The NRC agreed with the public comments to remove conditions 1, 2,
and 3 because the three conditions are the same as those for Section
III, Mandatory Appendix XXVI, which was conditionally accepted by the
NRC in Sec. 50.55a. It is redundant to specify these conditions to
Code Case N-886.
As a result of public comment, the NRC clarified condition 4 to
state that for aboveground applications, licensees must ensure that
plant fire protection program addresses any high-density polyethylene
(HDPE) consistent with the requirements of 10 CFR 50.48. The licensee
must identify the specific program to satisfy this objective such as
the plant fire protection program. Therefore, the condition is retained
in Revision 39 of RG 1.84.
The NRC agreed with the public comment to remove condition 5
because the requirement that carbon black distribution in HDPE pipe to
be homogenous to prevent windows and delamination is a pipe
manufacturing process issue. The staff determined that the requirements
in Mandatory Appendix XXVI-2231(b) adequately address this issue. Code
Case N-886 is only for design, and all materials must meet the
requirements of Appendix XXVI.
2. ASME BPV Code, Section XI Code Cases (RG 1.147)
Code Case N-513-5 [Supplement 6, 2017 Edition]
Type: Revised.
Title: Evaluation Criteria for Temporary Acceptance of Flaws in
Moderate Energy Class 2 or 3 Piping and Gate Valves, Section XI,
Division 1.
Code Case N-513-5 contains provisions to permit temporary
[[Page 11941]]
acceptance of flaws, in moderate energy Class 2 or 3 piping, including
elbows, pipe bends, reducers, expanders, branch tees, and gate valves
without performing a repair/replacement activity for a limited period.
The code case contains provisions regarding the scope, flaw
characterization, periodic leakage monitoring, flaw evaluation, and
augmented examinations. The NRC finds that the provisions of N-513-5
are acceptable except that the augmented examination provisions in
Section 5 of the code case require clarification.
When a licensee applies N-513-5 to disposition a through-wall leak
or wall thinning in a piping system, Section 5 of the code case
requires augmented examinations for flaws and significant flaws. The
augmented examination requirements in N-513-5 are the same as in Code
Case N-513-3.
In 2018, the NRC found an instance where a licensee misinterpreted
the provisions in Section 5 of N-513-3 and did not perform the required
augmented examinations to disposition a through-wall leak in a service
water system pipe. Other licensees have similarly misinterpreted the
augmented examination provisions in Section 5 of N-513-3. The NRC found
that the issue stems from the definition of the terms ``flaw'' and
``significant flaw'' in Sections 5(b) and 5(c) of N-513-3,
respectively. The NRC, therefore, imposes two conditions to define
``flaw'' and ``significant flaw'' as those terms are used in Section 5
of N-513-5. Licensees would be required to apply these definitions to
Section 5 when using the code case.
The first condition defines a ``flaw'' as a non-through-wall planar
or nonplanar flaw with a wall thickness less than 87.5 percent of the
nominal wall thickness of the pipe or the design minimum wall
thickness. The NRC notes that the pipe wall thickness at the time of
the plant construction may deviate from the nominal pipe wall thickness
slightly as part of manufacturing process. The generally accepted
deviation is 12.5 percent of the nominal pipe wall thickness or the
design minimum wall thickness.
The second condition defines ``significant flaw'' as any pipe
location that does not satisfy the provisions of Section 3 of N-513-5
or if any detected flaw that has a depth greater than 75 percent of the
pipe wall thickness. The NRC staff notes that the criterion of the 75
percent wall thickness criterion originates from the provisions of IWC/
IWD-3643 of the ASME Code, Section XI, which prohibits a flaw that
exceeds 75 percent of the pipe wall thickness to remain in service.
Under Section 5 of N-513-5, a planar flaw that exceeds 75 percent of
the pipe wall thickness may remain in service; however, the licensee
must perform an augmented examination. The NRC agreed with the public
comment that Condition 2 needed clarification. As a result, the NRC
revised Condition No. 2 as follows: ``For the purposes of section 5 of
Code Case N-513-5, the term ``significant flaw'' means any flaw found
during augmented examinations performed per Section 5 of N-513-5 that
has a depth greater than 75 percent of the pipe wall thickness or that
does not satisfy the applicable requirements of the flaw evaluation per
Section 3 of N-513-5. If a significant flaw as defined above is
present, then the licensee must perform the additional augmented
examination specified in Section 5.''
Code Case N-516-5 [Supplement 6, 2015 Edition]
Type: Revised.
Title: Underwater Welding, Section XI, Division 1.
In the rulemaking for the 2009 Addenda through 2013 Editions of the
ASME Code (82 FR 32934; September 18, 2017), the NRC-specified
conditions that should be applied to Section XI, Article IWA-4660 when
performing underwater welding on irradiated materials. These conditions
provide guidance on what level of neutron irradiation and/or helium
content would require review and approval by the NRC because of the
impact of neutron fluence on weldability. These conditions provide
separate criteria for three generic classes of material: Ferritic
material, austenitic material other than P-No. 8 (e.g., nickel-based
alloys) and austenitic P-No. 8 material (e.g., stainless steel alloys).
These conditions are currently located in Sec. 50.55a(b)(2)(xii)(A)
and (B). The conditions located in Sec. 50.55a(b)(2)(xii)(A) and (B)
are identical to the conditions that were imposed on Code Case N-516-4
that were approved by the NRC in Revision 19 of RG 1.147. When the ASME
revised N-516, the code case was not modified in a way that would make
it possible for the NRC to remove the conditions. Therefore, the
conditions are retained in Revision 20 of RG 1.147 by stating the
provisions of Sec. 50.55a(b)(2)(xii)(A) and (B) must be met when
applying this code case.
Code Case N-597-3 [Supplement 5, 2013 Edition]
Type: Revised.
Title: Evaluation of Pipe Wall Thinning, Section XI.
Based on public comments, the NRC found that existing Condition
2(b) references Figure-3622.1(a)(1), which does not exist in Code Case
N-597-3. The NRC revised Condition 2(b) in the final rule to reference
Figure 3622-1 of the code case.
Code Case N-705-1 [Supplement 2, 2017 Edition]
Type: Revised.
Title: Evaluation Criteria for Temporary Acceptance of Degradation
in Moderate Energy Class 2 or 3 Vessels and Tanks, Section XI, Division
1.
The condition on Code Case N-705-1 is identical to the condition on
N-705 that was approved by the NRC in Revision 19 of RG 1.147. When the
ASME revised N-705, the code case was not modified in a way that would
make it possible for the NRC to remove the condition. Therefore, the
condition is retained in Revision 20 of RG 1.147.
Code Case N-766-3 [Supplement 2, 2017 Edition]
Type: Revised.
Title: Nickel Alloy Reactor Coolant Inlay and Onlay for Mitigation
of Pressurized Water Reactor (PWR) Full Penetration Circumferential
Nickel Alloy Dissimilar Metal Welds in Class 1 Items, Section XI,
Division 1.
The conditions on Code Case N-766-3 are identical to the conditions
on N-766-1 that were approved by the NRC in Revision 19 of RG 1.147.
When the ASME revised N-766, the code case was not modified in a way
that would make it possible for the NRC to remove the conditions.
Therefore, the conditions are retained in Revision 20 of RG 1.147.
Code Case N-778 [Supplement 0, 2010 Edition]
Type: New.
Title: Alternative Requirements for Preparation and Submittal of
Inservice Inspection Plans, Schedules, and Preservice and Inservice
Inspection Summary Reports, Section XI, Division 1.
Code Case N-778 was originally listed in Table 2 of Revision 18 of
RG 1.147 with two conditions. As a result of public comments, the NRC
revised the second condition on Code Case N-778 to be consistent with
Code Case N-892 by increasing the time period for submittal of the
inservice inspection summary report to 120 days following the
completion of each refueling outage.
Code Case N-831-1 [Supplement 7, 2017 Edition]
Type: Revised.
Title: Ultrasonic Examination in Lieu of Radiography for Welds in
Ferritic or Austenitic Pipe, Section XI, Division 1.
[[Page 11942]]
The condition on Code Case N-831-1 is identical to the condition on
N-831 that was approved by the NRC in Revision 19 of RG 1.147. When
ASME revised N-831, the code case was not modified in a way that would
make it possible for the NRC to remove the condition. Therefore, the
condition is retained in Revision 20 of RG 1.147.
Code Case N-847 [Supplement 0, 2017 Edition]
Type: New.
Title: Partial Excavation and Deposition of Weld Metal for
Mitigation of Class 1 Items, Section XI, Division 1.
The ASME Code Case N-847 provides guidelines for a repair/
mitigation process for welds. The process, excavation and weld repair
(EWR), removes susceptible material from the outside diameter of the
pipe, and replaces it with more resistant weld material. This technique
allows for the potential of two mitigation methods, the use of more
crack-resistant material and the potential for compressive stresses on
the inside surface of the repaired/mitigated weld to arrest or prevent
cracking. Finally, the excavation can be done 360-degrees around the
weld or only for a partial arc of the weld.
The code case would allow for application of this process to both
BWR and PWR designs. However, the EWR process, as defined in this code
case, has certain challenges addressing the cracking mechanisms in
these operating environments and materials. In addition, the regulatory
requirements or guidelines related to the code case vary depending on
the design of the reactor. For PWR designs, the inservice inspection
rules are provided by Sec. 50.55a(g)(6)(ii)(F), which mandates the
implementation of a version of ASME Code Case N-770-5. For BWR designs,
the inservice inspection guidelines are provided by Generic Letter 88-
01, ``NRC Position on Intergranular Stress Corrosion Cracking (IGSCC)
in BWR Austenitic Stainless Steel Piping,'' or BWRVIP-75-A, ``BWR
Vessel and Internals Project Technical Basis for Revisions to Generic
Letter 88-01 Inspection Schedules.'' Therefore, the NRC is imposing six
conditions to ensure the inservice inspection frequency guidelines of
the code case are consistent with the previous requirements and
guidance, which are based on the effectiveness of the overall design of
the repair/mitigation to address the various cracking mechanisms of
these operating reactor designs.
The first condition is a continuation of the condition of Sec.
50.55a(g)(6)(ii)(F)(16), which requires that a partial arc EWR, as
described in Inspection Item O of ASME Code Case N-770-5, cannot be
used without NRC review and approval for PWR designs. The NRC notes
that the issues addressed in the final rule incorporating by reference
the 2015 and 2017 Editions of the ASME BPV Code and the 2015 and 2017
Editions of the ASME OM Code remain applicable, and further apply to
BWR design application of a partial arc EWR. These concerns are for the
effectiveness of the repair through a weld residual stress calculation
and flaw growth analysis to confirm design of the mitigation for the
required inspection interval, non-destructive examination uncertainty
analysis of the as-found flaw remaining in the reactor coolant pressure
boundary, and the potential for further crack initiation or growth. The
NRC requires, through the first condition, that approval of the use of
this code case is only for the application of the 360-degree EWR.
The second condition is related to Figure 1A and Figure 1B of the
code case. The NRC has experience with relief request submittals, where
the details associated with the configuration of the prep area, where
the defect is being removed, have shown sharp bottom edges and steep
walls. This geometry can result in welding issues, which could result
in unfused material, leading to stress risers, which may promote
cracking. The NRC requires, through the second condition, that the
intersection points at the interface between EWR metal and existing
base metal must be rounded to minimize stress concentration.
The third condition is related to Section 2(d) of the code case,
which discusses the flaw evaluations required for the design
considerations of the EWR. In recent testing conducted for the NRC
measurable stress corrosion cracking (SCC) growth was detected past the
interface between the SCC-susceptible and less susceptible material. It
was demonstrated that the crack can branch and propagate in a direction
normal to the original direction along a SCC-susceptible path. In the
Alloy 52M deposited onto Alloy 182 specimens tested, this occurred in
the diluted region of the Alloy 52M material as well as the weld metal.
The NRC requires, through the third condition, that flaw analysis
include the potential for crack growth through the dilution zone
including crack branching. As NRC-approved crack growth rates are not
available for all material types (e.g., Alloy 690 weld material), the
alternative requirements for development of crack growth rates should
be consistent with ASME Section XI Appendix C, ``Flaw Growth Rate Due
to Stress Corrosion Cracking,'' C-3220(a). As a result of public
comment, the NRC agrees this condition should be updated to reference
Section 2(d)(1), rather than 2(d)(2) as discussed in the proposed rule
(86 FR 7820, February 2, 2021), for nickel-based alloys. The NRC
clarified the condition to state the evaluation in Section 2(d)(1) of
the code case must include evaluation of crack growth into the Alloy
690 weld material, including the dilution zones and allowing change in
flaw growth direction.
The fourth condition is related to Section 2 of the code case. The
NRC is requiring the use of NUREG-2228, because it provides a proven
method for validating the weld residual stress analysis methodology.
Because the NRC requires the use of NUREG-2228 within this condition on
the requirements in the code case, the NRC is incorporating by
reference NUREG-2228 into Sec. 50.55a(a)(3)(iv).
The fifth condition is related to the longer-term volumetric
inspection frequencies of Table 1, including notes (1), (3), and (4).
These notes provide the BWR design inspection frequency of various EWR
types based on Generic Letter 88-01 (1988) as supplemented by Generic
Letter 88-01, Supplement 1 (1992), ``NRC Position on Intergranular
Stress Corrosion Cracking (IGSCC) in BWR Austenitic Stainless Steel
Piping,'' or BWRVIP-75-A, ``BWR Vessel and Internals Project Technical
Basis for Revisions to Generic Letter 88-01 Inspection Schedules.'' The
NRC has concluded that the inspection requirements for EWRs for BWRs
need to be augmented.
The first volumetric examination following application of BWR EWR-
2A, EWR-1B, and EWR-2B welds is performed to verify effectiveness of
the repair/mitigation before the new weld can be placed in a longer-
term volumetric inspection frequency. The code case allows licensees
the option of performing this examination during the first or second
refueling outage after installation. However, based on the lower
operating temperatures of a BWR (approximately 546 [deg]F to 558
[deg]F), and hence the potential slow crack growth rate of the
remaining flaw left in service, the NRC has concluded that the
examination should occur during the second refueling outage after the
EWR application to provide adequate time for any potential measurable
flaw growth to occur or in the case of an EWR-2A, for crack initiation
and growth to occur.
The long-term volumetric inspections for BWRs require modification
because: (a) For EWR-1A EWRs, the augmented
[[Page 11943]]
inspection requirements are consistent with the conditions of the
inspection frequencies of Code Case N-770-5. These inspection frequency
requirements were previously developed by the NRC based on the
capabilities of the EWR process to address stress corrosion cracking
while providing significant credit for the use of hydrogen water
chemistry/noble metal chemical addition controls; and (b) for EWR-1B
EWRs, the design that would allow a crack to be left in service, should
not be allowed to go uninspected for the remainder of plant life.
Therefore, the NRC requires the long-term volumetric inspection of
these welds at each 10-year inservice inspection interval. The NRC
notes that this condition is consistent with the NRC condition
established in Sec. 50.55a for Inspection Item N-1 EWRs (EWR that
meets stress criteria; however, a crack is present).
The sixth condition is related to Table 1, Note (1), and the option
to use an unspecified alternative to determine examination frequencies
and scope expansion criteria. Note (1) specifies the use of NRC Generic
Letter 88-01 and includes BWRVIP-75-A as an example of an alternative.
The NRC has concluded that NRC Generic Letter 88-01 (1988), as
supplemented by Generic Letter 88-01, Supplement 1 (1992), or BWRVIP-
75-A, are acceptable, subject to the fifth condition, to determine
examination frequencies and scope expansion criteria. However, Note (1)
would allow the use of other, unknown alternatives and does not provide
criteria to ensure alternatives are adequate for this purpose.
Therefore, to ensure that licensees use an adequate standard to
determine examination frequencies and scope expansion criteria, the
sixth condition requires that licensees must not use an alternative
other than those specified in Note (1).
Code Case N-864 [Supplement 2, 2017 Edition]
Type: New.
Title: Reactor Vessel Threads in Flange Examinations, Section XI,
Division 1.
Code Case N-864 eliminates the required ASME Code, Section XI
examination for the reactor vessel threads-in-flange for all inservice
inspection intervals. The NRC has previously granted alternatives under
Sec. 50.55a(z) that eliminate the reactor pressure vessel threads-in-
flange examinations (ASME Section XI, Examination Category B-G-1, Item
No. B6.40) for up to two inservice inspection intervals through the
NRC's alternative request process. For alternatives that requested
elimination of the examination for a second consecutive 10-year
inservice inspection interval, the NRC has been requesting additional
information on activities performed to ensure that the condition of the
reactor pressure vessel threads-in-flange receives some level of
monitoring. These activities typically have included care and
maintenance of the reactor vessel threads-in-flange (and studs)
whenever the closure head is removed. The NRC has limited approval of
such requests to two subsequent inservice inspection intervals because
the NRC has determined that complete elimination of the examinations
does not provide adequate protection against long-term degradation of
the threads-in-flange. The NRC is imposing conditions on the use of
Code Case N-864 that are consistent with the limits the NRC has placed
on similar alternatives requests.
The first condition in Code Case N-864 requires that the reactor
pressure vessel threads-in-flange examinations (ASME Section XI,
Examination Category B-G-1, Item No. B6.40) must be performed in at
least every third 10-year ISI interval. This condition also limits the
application of Code Case N-864 at facilities that have been authorized
under Sec. 50.55a(z) to use alternatives that eliminate reactor
pressure vessel threads-in-flange examinations to ensure that the
required examination is performed at least every third 10-year
inservice inspection interval.
The second condition in Code Case N-864 ensures that sufficient
monitoring and maintenance activities are performed and documented when
the code case is applied. As a result of public comments, the NRC
clarified that performing and documenting the facility's maintenance
procedures for removal, care, and visual inspection of the reactor head
closure studs and threads in flange during each refueling outage are
sufficient to satisfy the second condition.
Code Case N-869 [Supplement 6, 2017 Edition]
Type: New.
Title: Evaluation Criteria for Temporary Acceptance of Flaws in
Class 2 or 3 Piping, Section XI, Division 1.
Code Case N-869 contains provisions for temporary acceptance of
flaws, including through-wall flaws in Class 2 or 3 piping including
elbows, pipe bends, reducers, and branch tees, whose maximum operating
pressure is greater than 275 psig and does not exceed 600 psig, without
performing a repair/replacement activity. The code case contains
provisions regarding the scope, flaw characterization, periodic leakage
monitoring, flaw evaluation, and augmented examinations. The NRC finds
that the code case provides reasonable assurance that structural
integrity of degraded piping will be maintained until the next
scheduled refueling outage. However, the NRC finds that the augmented
examination provisions in Section 5 of the code case are unclear and
need additional clarification.
When a licensee applies N-869 to disposition a through-wall leak or
wall thinning in a piping system, Section 5 of the code case requires
augmented examinations for flaws and significant flaws. The augmented
examination requirements in N-869 are the same as in Code Case N-513-3.
In 2018, the NRC found an instance where a licensee misinterpreted
the provisions in Section 5 of N-513-3 and did not perform the required
augmented examinations to disposition a through-wall leak in a service
water system pipe. Other licensees have similarly misinterpreted the
augmented examination provisions in Section 5 of N-513-3. The NRC found
that the issue stems from the definition of the terms ``flaw'' and
``significant flaw'' in Sections 5(b) and 5(c) of N-513-3,
respectively. The NRC, therefore, imposes two conditions to define
``flaw'' and ``significant flaw'' as those terms are used in Section 5
of N-869. Licensees would be required to apply these definitions to
Section 5 when using the code case.
The first condition defines a ``flaw'' as a non-through-wall planar
or nonplanar flaw with a wall thickness less than 87.5 percent of the
nominal wall thickness of the pipe or the design minimum wall
thickness. The NRC notes that the pipe wall thickness at the time of
the plant construction may deviate from the nominal pipe wall thickness
slightly as part of manufacturing process. The generally accepted
deviation is 12.5 percent of the nominal pipe wall thickness or the
design minimum wall thickness.
The second condition defines ``significant flaw'' as any pipe
location that does not satisfy the provisions of Section 3 of N-869 or
if any detected flaw that has a depth greater than 75 percent of the
pipe wall thickness. The NRC staff notes that the 75 percent wall
thickness criterion originates from the provisions of IWC/IWD-3643 of
the ASME Code, Section XI, which prohibit a flaw that exceeds 75
percent of the pipe wall thickness to remain in service. Under Section
5 of N-869, a planar flaw that exceeds 75 percent of the pipe wall
[[Page 11944]]
thickness may remain in service; however, the licensee needs to perform
an augmented examination.
Code Case N-876 [Supplement 2, 2017 Edition]
Type: New.
Title: Austenitic Stainless Steel Cladding and Nickel Base Cladding
Using Ambient Temperature Automatic or Machine Dry Underwater Laser
Beam Welding (ULBW) Temper Bead Technique, Section XI, Division 1.
Some irradiated stainless steel reactor vessel internal components
are susceptible to experiencing irradiation assisted stress corrosion
cracking. Code Case N-876 provides guidelines for repair welding the
irradiated stainless steel components inside the reactor vessel. Code
Case N-876 provides an alternative to the cladding temper bead repair
rules of Section XI, IWA-4400, which requires preheat and postweld heat
treatment. This alternative establishes new rules governing ambient
temperature temper bead cladding repairs using the ULBW process.
The NRC is imposing two conditions on this code case. The first
condition that must be applied when performing ULBW on irradiated
materials provides guidance on what level of neutron irradiation and/or
helium content would require review and approval by the NRC because of
the impact of neutron fluence on weldability. The second condition
limits the depth of the cladding repair due to concerns with the
fracture toughness of the base metal.
The technical basis for imposing conditions on the welding of
irradiated materials are that neutrons can generate helium atoms within
the metal lattice through transmutation of various isotopes of boron
and/or nickel. At high temperatures, such as occurs during welding,
these helium atoms rapidly diffuse though the metal lattice, coalescing
and forming helium bubbles at the grain boundaries. In sufficient
concentration, these helium bubbles can cause grain boundary cracking
that occurs in the fusion zones and heat affected zones during the
heat-up/cooldown cycle.
The first condition applies conditions already applicable to Code
Case N-516-5 ``Underwater Welding Section XI, Division 1,'' that the
provisions of Sec. 50.55a(b)(2)(xii)(A) and (B) must be met. This
regulation provides limits on specific levels of neutron irradiation
and/or helium content, above which welding is prohibited without prior
NRC review and approval. The NRC is imposing the same condition to uses
of Code Case N-876.
The second condition is necessary because the code case does not
require impact testing of the base metal heat affected zone (HAZ) to
verify adequate fracture toughness. The code case allows the depth of
the repair cavity into the ferritic base metal to be up to \1/4\''.
This would allow welding directly to the base metal; thus, it will
affect the fracture toughness of the base metal in the HAZ. Therefore,
the NRC is imposing a condition restricting the use of the code case to
repairs where at least \1/8\'' of cladding remains. The basis for the
\1/8\'' limit is that this amount of austenitic material between the
ferritic base metal and the first weld layer has generally been
considered to sufficiently limit the heat input to the base metal such
that deleterious effects on the fracture toughness will not occur;
therefore, impact testing of the base metal is not necessary. The NRC
notes that Code Case N-803, which is approved without conditions,
allows repair of ferritic base material using nonferritic weld filler
material based on welding procedure qualifications performed using
tensile tests, side bends, and impact tests, and could be used to
perform a cladding repair in which excavation into the base metal is
required.
Code Case N-878 [Supplement 1, 2017 Edition]
Type: New.
Title: Alternative to QA Program Requirements of IWA-4142, Section
XI, Division 1.
Code Case N-878 provides alternatives to the quality assurance
requirements in IWA-4142 for procurement of Class 1, 2, or 3 non-welded
fittings. This code case addresses the testing and certification of
material used in the manufacture of non-welded fittings, but does not
address how the licensee must ensure that the procured non-welded
fittings meet the design and testing requirements of the ASME Code,
Section III, NB/NC/ND-3671.7 for Class 1, 2, or 3 applications.
Verification that the Section III requirements for the design and
testing of these non-welded fittings have been met prior to use is
essential in ensuring the structural integrity of these Class 1, 2 and
3 systems is maintained. Therefore, the NRC is imposing conditions for
the licensee to verify the design and testing activities associated
with qualification of non-welded fittings required by Section III, NB/
NC/ND-3671.7 that are performed by the fabricator.
The first condition states for ASME Section III items, the Licensee
must review the fabricator's design documentation and methods to ensure
the fittings design is in compliance with the Licensee's design
specifications, and ASME Section III NB/NC/ND-3671.7 requirements; and
either (1) supervise and monitor the performance qualification tests of
the fittings to ensure the design is in compliance with the Licensee's
design specifications and ASME Section III NB/NC/ND-3671.7, or (2) the
Licensee or Repair/Replacement Organization conducts qualification
tests of the fittings or conducts design analyses to ensure the design
is in compliance with the Licensee's design specifications and ASME
Section III NB/NC/ND-3671.7. In response to public comments, the NRC
clarified that for ASME Section III items, this condition applies only
for those licensees that implemented ASME Code, Section III design
requirements for their original construction code and/or the licensees
that have upgraded their original design requirements to ASME Code,
Section III.
The second condition states that the Licensees must give the
Authorized Nuclear Inservice Inspector an opportunity to review the
design report prior to installation.
Code Case N-880 [Supplement 2, 2017 Edition]
Type: New.
Title: Alternative to Procurement Requirements of IWA-4143 for
Small Nonstandard Welded Fittings, Section XI, Division 1.
Code Case N-880 provides alternatives to the material procurement
requirements of IWA-4142 and IWA-4143 for small nonstandard welded
fittings. This code case does not address how the licensee must ensure
the procured welded fittings meet the design and testing requirements
of the ASME Code, Section III, NB/NC/ND-3671.7 for Class 1, 2, or 3
applications. Verification that the Section III requirements for the
design and testing of these welded fittings have been met prior to use
is essential in ensuring the structural integrity of these Class 1, 2
and 3 systems is maintained. Therefore, the NRC is imposing conditions
requiring the licensee to verify the design and testing activities
associated with qualification of welded fittings required by Section
III, NB/NC/ND-3671.7 that are performed by the fabricator.
The first condition states for ASME Section III items, the Licensee
must review the fabricator's design documentation and methods to ensure
the fittings design is in compliance with the Licensee's design
specifications, and ASME Section III NB/NC/ND-3671.7 requirements; and
either: (1) Supervise
[[Page 11945]]
and monitor the performance qualification tests of the fittings to
ensure the design is in compliance with the Licensee's design
specifications and ASME Section III NB/NC/ND-3671.7, or (2) the
Licensee or Repair/Replacement Organization conducts qualification
tests of the fittings or conducts design analyses to ensure the design
is in compliance with the Licensee's design specifications and ASME
Section III NB/NC/ND-3671.7. In response to public comments, the NRC
clarified that for ASME Section III items, this condition applies only
for those licensees that implemented ASME Code, Section III design
requirements for their original construction code and/or the licensees
that have upgraded their original design requirements to ASME Code,
Section III.
The second condition states that the Licensees must give the
Authorized Nuclear Inservice Inspector an opportunity to review the
design report prior to installation.
Code Case N-889 [Supplement 7, 2017 Edition]
Type: New.
Title: Reference Stress Corrosion Crack Growth Rate Curves for
Irradiated Austenitic Stainless Steel in Light-Water Reactor
Environments, Section XI, Division 1.
Code Case N-889 provides a new crack growth rate (CGR) law for
irradiation-assisted stress corrosion cracking. The code case is
applicable to wrought austenitic stainless steels and associated weld
metals, as well as cast austenitic stainless steels. The proposed CGR
law requires the user to first calculate irradiated yield stress from
the dose to the material. There are two yield stress models: One for
Molybdenum bearing stainless steels and one for stainless steels
without Molybdenum. Once irradiated yield stress has been determined,
the user calculates the CGR as a function of applied crack driving
force and temperature.
The staff identified three concerns with the technical basis of
this code case. The first concern relates to the limited CGR data at
dose levels greater than 20 displacements per atom (dpa). The proposed
CGR law indicates that the irradiated yield stress (and, consequently,
the CGR) increases with fluence up to a dose of 20 dpa, at which point
the irradiated yield's stress ceases to increase appreciably with
further dose accumulation. While the data at dose levels greater than
20 dpa does show a plateau behavior in the CGR, the staff's analyses of
that data suggests that areas of high CGR were averaged over the
industry calculation of CGR, which increases the uncertainty in the
high dose CGRs. Therefore, due to the limited data and the associated
high uncertainty at high fluence, the staff's confidence in CGRs at
dose levels greater than 20 dpa is low.
The second concern is the effects of uncertainty in the irradiated
yield strength value for an individual material-heat. This topic is
discussed in Section 4.7 of the technical basis report for Code Case N-
889. The NRC also conducted separate analyses. While the results of the
NRC's findings are generally consistent with the results in Section
4.7, the interpretation of their significance is not consistent. For
materials with yield strengths greater than 600 MPa (i.e., more highly-
irradiated materials), the expected CGR for a material with a yield
strength in the 95th percentile is less than two times the CGR
predicted by the code case, which is not a significant difference.
However, for materials with yield strength values less than 250 MPa
(i.e., unirradiated or minimally irradiated materials), the expected
CGR for a material in the 95th percentile can be more than five times
greater than the CGR predicted by the code case. Hence, the NRC's
concern is that the CGRs for individual low yield strength materials,
or materials with low fluence, could be significantly underpredicted by
the code case.
The final concern is related to the data used in the development of
the irradiated yield stress model. The methodology for addressing cold
work in this model was developed in MRP-135, Revision 1, while the
model itself was developed in MRP-211, Revision 0. The database
underlying the model included hundreds of yield strength measurements
on initially annealed and cold-worked Types 304, 316, and 347/348
stainless steel materials. However, most of the data were for annealed
Type 304 and cold-worked Type 316 stainless steels. Revision 1 of MRP-
211 contained additional yield strength data, including significantly
more data for cold-worked Types 304 and 347 stainless steel. The
authors of the code case, as documented in Section 4.5 of the
Additional Basis Report dated February 5, 2018, evaluated the code case
yield stress model with some of this additional data and found
agreement between the model and the additional data. However, the code
case authors excluded new data for cold-worked Type 304 and 347
stainless steel materials. Therefore, the technical basis document for
Code Case N-889 does not directly address whether cold-worked Type 304
and 347 (non-Molybdenum bearing) materials are adequately predicted by
the irradiated yield strength model in the code case. The NRC is
imposing three conditions on this code case.
The first condition states that this code case may not be applied
for neutron exposures greater than 20 dpa. This condition addresses the
NRC concern that there is sparse data with high uncertainty beyond 20
dpa. Given that the predicted CGR saturates at higher fluence, this
condition prevents potential underprediction of the CGR in this fluence
regime.
The second condition states that at dose levels below 0.75 dpa, the
user must use the higher of the Code Case N-889 or the Section XI,
Nonmandatory Appendix C, C-8520 CGR predictions. This condition
addresses the NRC concern related to possible underprediction of CGR in
Code Case N-889 for materials with calculated irradiated yield strength
less than 250 MPa.
The final condition states that the irradiated yield stress model
for cold-worked Molybdenum bearing materials must be used for cold-
worked non-Molybdenum bearing stainless steels (including Type 204 and
247 stainless steels). This condition addresses the NRC concern that
data for cold-worked non-Molybdenum bearing steels were not
appropriately considered during development of Code Case N-889. The NRC
performed its own evaluation of cold-worked Type 304 and 347 stainless
steels in the MRP-211 database and found that the yield strength was
better predicted by the code case's Molybdenum bearing model than with
the code case's non-Molybdenum bearing model.
Code Case N-890 [Supplement 0, 2019 Edition]
Type: New.
Title: Materials Exempted From G-2110(b) Requirements, Section XI,
Division 1.
Code Case N-890 provides an alternative to Section XI, G-2110(b)
which removes the requirement of, ``obtaining fracture toughness data
for at least three heats,'' for using the static fracture toughness
curve (Klc) curve for specific materials with a minimum
specified yield strength at room temperature between 50 kilopound per
square inch (ksi) and 90 ksi. Code Case N-890 would allow the toughness
of four ferritic steels (SA-508 Grade 2 Class 2, SA-508 Grade 3 Class
2, SA-533 Type A Class 2 and SA-533 Type B Class 2) with specified
minimum yield strength greater than 50 ksi to be characterized by
Figure G-2110-1 (i.e., the Section XI Klc curve).
[[Page 11946]]
The NRC identified one technical concern when reviewing the
technical basis of this code case. The technical basis provided
appropriate data to justify use of the Klc curve for several
materials listed in the code case. However, for SA-533 Type B, Class 2
materials, the NRC observed that in the technical basis document, there
is no fracture toughness data associated with the weld and heat
affected zone to support exclusion of the fracture toughness testing
requirements for these materials.
As such, the imposed NRC condition requires the user to comply with
the provisions of Section III, NB-2300 and Section III, G-2110(b) to
demonstrate the applicability of the ASME Klc curve to SA-
533 Type B, Class 2 material. These provisions require the user to
generate the necessary toughness data to demonstrate that the ASME
KIC curve is a conservative representation of the actual
material toughness.
3. ASME Operation and Maintenance Code Cases (RG 1.192)
Code Case OMN-1, Revision 2 [2020 Edition]
Type: Reaffirmed.
Title: Alternative Rules for Preservice and Inservice Testing of
Active Electric Motor-Operated Valve Assemblies in Light-Water Reactor
Power Plants.
The conditions on Code Case OMN-1, Revision 2 [2020 Edition] are
identical to the conditions on OMN-1, Revision 2 [2017 Edition] that
were approved by the NRC in Revision 3 of RG 1.192. The OMN-1, Revision
2 was reaffirmed by the ASME in the 2020 Edition with no change to the
code case. Therefore, the conditions are retained in Revision 4 of RG
1.192.
Code Case OMN-3 [2020 Edition]
Type: Reaffirmed.
Title: Requirements for Safety Significance Categorization of
Components Using Risk Insights for Inservice Testing of LWR Power
Plants.
The conditions on Code Case OMN-3 [2020 Edition] are identical to
the conditions on OMN-3 [2017 Edition] that were approved by the NRC in
Revision 3 of RG 1.192. The OMN-3 was reaffirmed by the ASME in the
2020 Edition with no change to the code case. Therefore, the conditions
are retained in Revision 4 of RG 1.192.
Code Case OMN-4 [2020 Edition]
Type: Reaffirmed.
Title: Requirements for Risk Insights for Inservice Testing of
Check Valves at LWR Power Plants.
The conditions on Code Case OMN-4 [2020 Edition] are identical to
the conditions on OMN-4 [2017 Edition] that were approved by the NRC in
Revision 3 of RG 1.192. The OMN-4 was reaffirmed by the ASME in the
2020 Edition with no change to the code case. Therefore, the conditions
are retained in Revision 4 of RG 1.192.
Code Case OMN-9 [2020 Edition]
Type: Reaffirmed.
Title: Use of a Pump Curve for Testing.
The conditions on Code Case OMN-9 [2020 Edition] are identical to
the conditions on OMN-9 [2017 Edition] that were approved by the NRC in
Revision 3 of RG 1.192. The OMN-9 was reaffirmed by the ASME in the
2020 Edition with no change to the code case. Therefore, the conditions
are retained in Revision 4 of RG 1.192.
Code Case OMN-12 [2020 Edition]
Type: Reaffirmed.
Title: Alternative Requirements for Inservice Testing Using Risk
Insights for Pneumatically and Hydraulically Operated Valve Assemblies
in Light-Water Reactor Power Plants (OM-Code 1998, Subsection ISTC).
The conditions on Code Case OMN-12 [2020 Edition] are identical to
the conditions on OMN-12 [2017 Edition] that were approved by the NRC
in Revision 3 of RG 1.192. The OMN-12 was reaffirmed by the ASME in the
2020 Edition with no change to the code case. Therefore, the conditions
are retained in Revision 4 of RG 1.192.
Code Case OMN-19 [2020 Edition]
Type: Reaffirmed.
Title: Alternative Upper Limit for the Comprehensive Pump Test.
The conditions on Code Case OMN-19 [2020 Edition] are identical to
the conditions on OMN-19 [2017 Edition] that were approved by the NRC
in Revision 3 of RG 1.192. The OMN-19 was reaffirmed by the ASME in the
2020 Edition with no change to the code case. Therefore, the conditions
are retained in Revision 4 of RG 1.192.
Code Case OMN-20 [2020 Edition]
Type: Reaffirmed.
Title: Inservice Test Frequency.
The conditions on Code Case OMN-20 [2020 Edition] are identical to
the conditions on OMN-20 [2017 Edition] that were approved by the NRC
in Revision 3 of RG 1.192. The OMN-20 was reaffirmed by the ASME in the
2020 Edition with no change to the code case. Therefore, the conditions
are retained in Revision 4 of RG 1.192.
C. ASME Code Cases Not Approved for Use (RG 1.193)
The ASME code cases that are currently issued by the ASME, but not
approved for generic use by the NRC, are listed in RG 1.193, ``ASME
Code Cases not Approved for Use.'' In addition to the ASME code cases
that the NRC has found to be technically or programmatically
unacceptable, RG 1.193 includes code cases on reactor designs for high-
temperature gas-cooled reactors and liquid metal reactors, reactor
designs not currently licensed by the NRC, and certain requirements in
Section III, Division 2, for submerged spent fuel waste casks, that are
not endorsed by the NRC. RG 1.193 complements RGs 1.84, 1.147, and
1.192. It should be noted that the NRC is not adopting any of the code
cases listed in RG 1.193.
III. Opportunities for Public Participation
The proposed rule and draft RGs were published in the Federal
Register on February 2, 2021 (86 FR 7820), for a 60-day comment period.
The public comment period closed on April 5, 2021.
IV. Public Comment Analysis
The NRC published the proposed rule and draft regulatory guides for
public comment in the Federal Register. The NRC received 13 comment
submissions. A comment submission is a communication or document
submitted to the NRC by an individual or entity, with one or more
individual comments addressing a subject or issue. Private citizens
provided five comment submissions, nuclear industry organizations
provided five comment submissions, a foreign government entity provided
one comment submission, an anonymous commenter provided one comment
submission, and a science advocacy group provided one comment
submission.
The comment submissions generally addressed the code cases and
their proposed conditions, with five comment submissions objecting to
incorporation of a code case with no conditions in this rulemaking
activity. The NRC received a number of comments that were outside the
scope of this rulemaking, such as comments that discuss code cases
annulled after the publication of the supplements being considered in
this rulemaking. The latter group out of scope comments will be
considered in a future rulemaking.
The public comment submittals are available from the Federal e-
Rulemaking website at https://www.regulations.gov
[[Page 11947]]
under Docket ID NRC-2017-0025. The NRC prepared a summary and analysis
of public comments received on the 2020 proposed rule and draft
regulatory guides, which is available as indicated in the
``Availability of Documents'' section of this document. Responses to
the public comments, including a summary of how the final rule text or
guidance changed as a result of the public comments, can be found in
the public comment analysis.
For more information about the associated guidance documents, see
the ``Availability of Guidance'' section of this document.
V. Section-by-Section Analysis
The following paragraphs in Sec. 50.55a are revised:
Paragraph (a) Introductory Text
This final rule revises the last sentence to update the contact
information for the National Archives and Records Administration.
Paragraph (a)(1) Introductory Text
This final rule corrects a printing error by removing the line
break after ``telephone:''.
Paragraph (a)(3) Introductory Text
This final rule adds a reference to new paragraph (a)(3)(iv), which
indicates that NUREG-2228 is acceptable as specified in the conditions
when implementing code cases listed in certain NRC regulatory guides.
Paragraph (a)(3)(i)
This final rule revises the reference to ``NRC Regulatory Guide
1.84, Revision 38,'' by removing ``Revision 38'' and adding in its
place ``Revision 39'' and changes the month and year for the document's
revision date.
Paragraph (a)(3)(ii)
This final rule revises the reference to ``NRC Regulatory Guide
1.147, Revision 19'' by removing ``Revision 19'' and adding in its
place ``Revision 20'' and changes the month and year for the document's
revision date.
Paragraph (a)(3)(iii)
This final rule revises the reference to ``NRC Regulatory Guide
1.192, Revision 3'' by removing ``Revision 3'' and adding in its place
``Revision 4'' and changes the month and year for the document's
revision date.
Paragraph (a)(3)(iv)
This final rule adds new paragraph (a)(3)(iv) to reference NUREG-
2228, ``Weld Residual Stress Finite Element Analysis Validation: Part
II--Proposed Validation Procedure,'' Published July 2020 (including
Errata September 22, 2021), which is referenced in RG 1.147, Revision
20.
Paragraph (b)(1)(ii), Table 1
This final rule revises the reference to table 1 in the text of the
paragraph, and designates the table and revises the heading of the
table to conform to Office of the Federal Register (OFR) codification
requirements.
Paragraph (b)(2)(xv)(K)(4), Table 2
This final rule designates the table and revises the heading of the
table to conform to OFR codification requirements.
Paragraph (b)(3)(iv), Table 3
This final rule designates the table and revises the heading of the
table to conform to OFR codification requirements, and capitalizes the
word ``(Years)'' in two of the three column headings.
VI. Regulatory Flexibility Certification
As required by the Regulatory Flexibility Act (5 U.S.C. 605(b)),
the Commission certifies that this rule, if adopted, will not have a
significant economic impact on a substantial number of small entities.
This final rule affects only the licensing and operation of nuclear
power plants. The companies that own these plants do not fall within
the scope of the definition of ``small entities'' set forth in the
Regulatory Flexibility Act or the size standards established by the NRC
(Sec. 2.810).
VII. Regulatory Analysis
The NRC has prepared a regulatory analysis on this regulation. The
analysis examines the costs and benefits of the alternatives considered
by the NRC. The NRC did not receive public comments on the draft
regulatory analysis. The final regulatory analysis is available as
indicated in the ``Availability of Documents'' section of this
document.
VIII. Backfitting and Issue Finality
The provisions in this final rule allow licensees and applicants to
voluntarily apply NRC-approved code cases, sometimes with NRC-specified
conditions. The approved code cases are listed in three RGs that are
incorporated by reference into Sec. 50.55a. An applicant's or a
licensee's voluntary application of an approved code case does not
constitute backfitting, because there is no imposition of a new
requirement or new position.
Similarly, voluntary application of an approved code case by a 10
CFR part 52 applicant or licensee does not represent NRC imposition of
a requirement or action, and therefore is not inconsistent with any
issue finality provision in 10 CFR part 52. For these reasons, the NRC
finds that this final rule does not involve any provisions requiring
the preparation of a backfit analysis or documentation demonstrating
that one or more of the issue finality criteria in 10 CFR part 52 are
met.
IX. Plain Writing
The Plain Writing Act of 2010 (Pub. L. 111-274) requires Federal
agencies to write documents in a clear, concise, and well-organized
manner. The NRC has written this document to be consistent with the
Plain Writing Act as well as the Presidential Memorandum, ``Plain
Language in Government Writing,'' published June 10, 1998 (63 FR
31885).
X. Environmental Assessment and Final Finding of No Significant
Environmental Impact
The Commission has determined under the National Environmental
Policy Act of 1969, as amended, and the Commission's regulations in
subpart A of 10 CFR part 51, that this rule, if adopted, would not be a
major Federal action significantly affecting the quality of the human
environment; therefore, an environmental impact statement is not
required.
The determination of this environmental assessment is that there
will be no significant effect on the quality of the human environment
from this action. The NRC did not receive public comments regarding any
aspect of this environmental assessment.
As voluntary alternatives to the ASME Code, NRC-approved code cases
provide an equivalent level of safety. Therefore, the probability or
consequences of accidents is not changed. There are also no
significant, non-radiological impacts associated with this action
because no changes would be made affecting non-radiological plant
effluents and because no changes would be made in activities that would
adversely affect the environment. The determination of this
environmental assessment is that there will be no significant offsite
impact to the public from this action.
XI. Paperwork Reduction Act
This final rule amends collections of information subject to the
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). The
collections of information were approved by the Office of Management
and Budget, approval number 3150-0011.
Because the rule will reduce the burden for existing information
collections, the public burden for the
[[Page 11948]]
information collections is expected to be decreased by 230 hours per
response. This reduction includes the time for reviewing instructions,
searching existing data sources, gathering and maintaining the data
needed, and completing and reviewing the information collection.
The information collection is being conducted to document the plans
for and the results of inservice inspection and inservice testing
programs. The records are generally historical in nature and provide
data on which future activities can be based. Information will be used
by the NRC to determine if ASME BPV and OM Code provisions for
construction, inservice inspection, repairs, and inservice testing are
being properly implemented in accordance with Sec. 50.55a of the NRC
regulations, or whether specific enforcement actions are necessary.
Responses to this collection of information are mandatory under Sec.
50.55a.
You may submit comments on any aspect of the information
collections, including suggestions for reducing the burden, by the
following methods:
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2017-0025.
Mail comments to: FOIA, Library, and Information
Collections Branch, Office of the Chief Information Officer, Mail Stop:
T-6 A10M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001
or to the OMB reviewer at: OMB Office of Information and Regulatory
Affairs (3150-0011) Attn: Desk Officer for the Nuclear Regulatory
Commission, 725 17th Street NW, Washington, DC 20503; email:
[email protected].
Public Protection Notification
The NRC may not conduct or sponsor, and a person is not required to
respond to, a collection of information unless the document requesting
or requiring the collection displays a currently valid OMB control
number.
XII. Congressional Review Act
This final rule is a rule as defined in the Congressional Review
Act (5 U.S.C. 801-808). However, the Office of Management and Budget
has not found it to be a major rule as defined in the Congressional
Review Act.
XIII. Voluntary Consensus Standards
The National Technology Transfer and Advancement Act of 1995,
Public Law 104-113, requires that Federal agencies use technical
standards that are developed or adopted by voluntary consensus
standards bodies unless using such a standard is inconsistent with
applicable law or is otherwise impractical. In this final rule, the NRC
is continuing to use the ASME BPV and OM code cases, which are ASME-
approved voluntary alternatives to compliance with various provisions
of the ASME BPV and OM Codes. The NRC's approval of the ASME code cases
is accomplished by amending the NRC's regulations to incorporate by
reference the latest revisions of the following, which are the subject
of this rulemaking, into Sec. 50.55a: RG 1.84, Revision 39; RG 1.147,
Revision 20; RG 1.192, Revision 4; and NUREG-2228. The RGs list the
ASME code cases that the NRC has approved for use. The ASME code cases
are national consensus standards as defined in the National Technology
Transfer and Advancement Act of 1995 and OMB Circular A-119. The ASME
code cases constitute voluntary consensus standards, in which all
interested parties (including the NRC and licensees of nuclear power
plants) participate.
XIV. Incorporation by Reference-Reasonable Availability to Interested
Parties
The NRC is incorporating by reference three NRC RGs that list new
and revised ASME code cases that the NRC has approved as voluntary
alternatives to certain provisions of NRC-required editions and addenda
of the ASME BPV Code and the ASME OM Code. These regulatory guides are
RG 1.84, Revision 39; RG 1.147, Revision 20; and RG 1.192, Revision 4.
The NRC is also incorporating by reference NUREG-2228, which is
referenced in RG 1.147, Revision 20. As described in this document,
this report pertains to a condition on Code Case N-847.
The NRC is required by law to obtain approval for incorporation by
reference from the OFR. The OFR's requirements for incorporation by
reference are set forth in 1 CFR part 51. The discussion in this
section complies with the requirement for final rules as set forth in 1
CFR 51.5(b)(2).
The NRC considers ``interested parties'' to include all potential
NRC stakeholders, not only the individuals and entities regulated or
otherwise subject to the NRC's regulatory oversight. These NRC
stakeholders are not a homogenous group, so the considerations for
determining ``reasonable availability'' vary by class of interested
parties. The NRC identified six classes of interested parties with
regard to the material to be incorporated by reference in an NRC rule:
Individuals and small entities regulated or otherwise
subject to the NRC's regulatory oversight. This class includes
applicants and potential applicants for licenses and other NRC
regulatory approvals, and who are subject to the material to be
incorporated by reference. In this context, ``small entities'' has the
same meaning as set out in Sec. 2.810.
Large entities otherwise subject to the NRC's regulatory
oversight. This class includes applicants and potential applicants for
licenses and other NRC regulatory approvals, and who are subject to the
material to be incorporated by reference. In this context, a ``large
entity'' is one that does not qualify as a ``small entity'' under Sec.
2.810.
Non-governmental organizations with institutional
interests in the matters regulated by the NRC.
Other Federal agencies, states, local governmental bodies
(within the meaning of Sec. 2.315(c)).
Federally-recognized and State-recognized Indian tribes.
Members of the general public (i.e., individual,
unaffiliated members of the public who are not regulated or otherwise
subject to the NRC's regulatory oversight) who need access to the
materials that the NRC proposes to incorporate by reference in order to
participate in the rulemaking.
The NUREG-2228 and three RGs that the NRC is incorporating by
reference in this final rule are available without cost and can be read
online or downloaded online. The NUREG-2228 and three RGs can be
viewed, by appointment, at the NRC Technical Library, which is located
at Two White Flint North, 11545 Rockville Pike, Rockville, Maryland
20852; telephone: 301-415-7000; email: [email protected].
Because access to NUREG-2228 and the three final regulatory guides
is available in various forms at no cost, the NRC determines that
NUREG-2228 and the three final regulatory guides, RG 1.84, Revision 39;
RG 1.147, Revision 20; and RG 1.192, Revision 4, once approved by the
OFR for incorporation by reference, are reasonably available to all
interested parties.
[[Page 11949]]
Table III--Regulatory Guides Incorporated by Reference in 10 CFR 50.55a
------------------------------------------------------------------------
ADAMS Accession
Document title No./ Federal
Register citation
------------------------------------------------------------------------
RG 1.84, Design, Fabrication, and Materials Code Case ML21181A225
Acceptability, ASME Section III, Revision 39........
RG 1.147, Inservice Inspection Code Case ML21181A222
Acceptability, ASME Section XI, Division 1, Revision
20..................................................
RG 1.192, Operation and Maintenance Code Case ML21181A223
Acceptability, ASME OM Code, Revision 4.............
------------------------------------------------------------------------
Table IV--Related Documents Incorporated by Reference in 10 CFR 50.55a
------------------------------------------------------------------------
ADAMS Accession
Document title No./ Federal
Register citation
------------------------------------------------------------------------
NUREG-2228, ``Weld Residual Stress Finite Element ML20212L592
Analysis Validation: Part II--Proposed Validation
Procedure,'' July 2020..............................
------------------------------------------------------------------------
XV. Availability of Guidance
The NRC is issuing revised guidance, RG 1.193, ``ASME Code Cases
Not Approved for Use,'' Revision 7, for the implementation of the
requirements in this final rule. The guidance is available as indicated
in Section XVI, ``Availability of Documents,'' of this document. You
may access information and comment submissions related to the guidance
by searching on https://www.regulations.gov under Docket ID NRC-2017-
0025.
The regulatory guide lists code cases that the NRC has not approved
for generic use and will not be incorporated by reference into the
NRC's regulations.
XVI. Availability of Documents
The documents identified in the following table are available to
interested persons through one or more of the following methods, as
indicated.
------------------------------------------------------------------------
ADAMS Accession
No./web link/
Document Federal Register
citation
------------------------------------------------------------------------
RG 1.84, Design, Fabrication, and Materials Code Case ML21181A225
Acceptability, ASME Section III, Revision 39,
December 2021.......................................
RG 1.147, Inservice Inspection Code Case ML21181A222
Acceptability, ASME Section XI, Division 1, Revision
20, December 2021...................................
RG 1.192, Operation and Maintenance Code Case ML21181A223
Acceptability, ASME OM Code, Revision 4, December
2021................................................
RG 1.193, ASME Code Cases Not Approved for Use, ML21181A224
Revision 7..........................................
NUREG-2228, ``Weld Residual Stress Finite Element ML20212L592
Analysis Validation: Part II-Proposed Validation
Procedure,'' July 2020..............................
Rulemaking-Proposed Rule-Draft Regulatory Analysis ML20133K152
for the American Society of Mechanical Engineers
Code Cases, RG 1.84, Rev 39; RG 1.147, Rev 20; RG
1.192 Rev 4.........................................
Rulemaking-Final Rule-Final Regulatory Analysis for ML21196A096
the American Society of Mechanical Engineers Code
Cases, RG 1.84, Rev 39; RG 1.147, Rev 20; RG 1.192
Rev 4...............................................
NRC Responses to Public Comments..................... ML21196A100
Proposed Rule-Approval of American Society of ML20132A241
Mechanical Engineers Code Cases RG 1.84, Rev 39; RG
1.147, Rev 20; RG 1.192 Rev 4.......................
Proposed Rule-Approval of American Society of 86 FR 7820
Mechanical Engineers Code Cases RG 1.84, Rev 39; RG
1.147, Rev 20; RG 1.192 Rev 4.......................
Final Rule-Approval of American Society of Mechanical 85 FR 14736
Engineers Code Cases RG 1.84, Rev 38; RG 1.147, Rev
19; RG 1.192 Rev 3..................................
------------------------------------------------------------------------
List of Subjects in 10 CFR Part 50
Antitrust, Classified information, Criminal penalties, Fire
protection, Incorporation by reference, Intergovernmental relations,
Nuclear power plants and reactors, Radiation protection, Reactor siting
criteria, Reporting and recordkeeping requirements.
For the reasons set out in the preamble and under the authority of
the Atomic Energy Act of 1954, as amended; the Energy Reorganization
Act of 1974, as amended; and 5 U.S.C. 552 and 553, the NRC is adopting
the following amendments to 10 CFR part 50:
PART 50--DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION
FACILITIES
0
1. The authority citation for part 50 continues to read as follows:
Authority: Atomic Energy Act of 1954, secs. 11, 101, 102, 103,
104, 105, 108, 122, 147, 149, 161, 181, 182, 183, 184, 185, 186,
187, 189, 223, 234 (42 U.S.C. 2014, 2131, 2132, 2133, 2134, 2135,
2138, 2152, 2167, 2169, 2201, 2231, 2232, 2233, 2234, 2235, 2236,
2237, 2239, 2273, 2282); Energy Reorganization Act of 1974, secs.
201, 202, 206, 211 (42 U.S.C. 5841, 5842, 5846, 5851); Nuclear Waste
Policy Act of 1982, sec. 306 (42 U.S.C. 10226); National
Environmental Policy Act of 1969 (42 U.S.C. 4332); 44 U.S.C. 3504
note; Sec. 109, Pub. L. 96-295, 94 Stat. 783.
0
2. In Sec. 50.55a:
0
a. Revise the last sentence of paragraph (a) introductory text and
paragraphs (a)(1) introductory text and (a)(3) introductory text;
0
b. In paragraph (a)(3)(i):
0
i. Remove the text ``Revision 38'' and add in its place the text
``Revision 39''; and
0
ii. Remove the text ``dated October 2019'' and add in its place the
text ``issued December 2021'';
0
c. In paragraph (a)(3)(ii):
[[Page 11950]]
0
i. Remove the text ``Revision 19'' and add in its place the text
``Revision 20''; and
0
ii. Remove the text ``dated October 2019'' and add in its place the
text ``issued December 2021'';
0
d. In paragraph (a)(3)(iii):
0
i. Remove the text ``Revision 3'' and add in its place the text
``Revision 4''; and
0
ii. Remove the text ``dated October 2019'' and add in its place the
text ``issued December 2021'';
0
e. Add paragraph (a)(3)(iv);
0
f. In paragraph (b)(1)(ii), remove the text ``Table I of this section''
and add in its place the text ``table 1 to this paragraph (b)(1)(ii)'';
0
g. Designate the table immediately following paragraph (b)(1)(ii) as
table 1 to paragraph (b)(1)(ii) and revise the heading of the newly
designated table;
0
h. Designate the table immediately following paragraph (b)(2)(xv)(K)(4)
as table 2 to paragraph (b)(2)(xv)(K)(4) and revise the heading of the
newly designated table; and
0
i. Designate the table immediately following paragraph (b)(3)(iv) as
table 3 to paragraph (b)(3)(iv) and revise the heading and column
headings of the newly designated table.
The revisions and addition read as follows:
Sec. 50.55a Codes and standards.
(a) * * * For information on the availability of this material at
NARA, email [email protected] or go to www.archives.gov/federal-register/cfr/ibr-locations.html.
(1) American Society of Mechanical Engineers (ASME), Three Park
Avenue, New York, NY 10016; telephone: 1-800-843-2763; https://www.asme.org/Codes/.
* * * * *
(3) U.S. Nuclear Regulatory Commission (NRC) Public Document Room,
11555 Rockville Pike, Rockville, Maryland 20852; telephone: 1-800-397-
4209; email: [email protected]; https://www.nrc.gov/reading-rm/doc-collections/reg-guides/. The use of code cases listed in the NRC
regulatory guides in paragraphs (a)(3)(i) through (iii) of this section
is acceptable with the specified conditions in those guides when
implementing the editions and addenda of the ASME BPV Code and ASME OM
Code incorporated by reference in paragraph (a)(1) of this section. The
NRC report in paragraph (a)(3)(iv) of this section is acceptable as
specified in the conditions when implementing code cases listed in the
NRC regulatory guides in paragraphs (a)(3)(i) through (iii) of this
section.
* * * * *
(iv) NUREG-2228. NUREG-2228, ``Weld Residual Stress Finite Element
Analysis Validation: Part II--Proposed Validation Procedure,''
Published July 2020 (including Errata September 22, 2021), which is
referenced in RG 1.147, Revision 20.
* * * * *
(b) * * *
(1) * * *
(ii) * * *
Table 1 to Paragraph (b)(1)(ii)--Prohibited Code Provisions
* * * * *
(2) * * *
(xv) * * *
(K) * * *
(4) * * *
Table 2 to Paragraph (b)(2)(xv)(K)(4)--Table VIII: S7-1--Modified
* * * * *
(3) * * *
(iv) * * *
Table 3 to Paragraph (b)(3)(iv)--Maximum Intervals for Use When Applying
Interval Extensions
------------------------------------------------------------------------
Maximum interval Maximum interval
between activities between activities
Group size of member valves in of each valve in the
the groups (years) group (years)
------------------------------------------------------------------------
* * * * * * *
------------------------------------------------------------------------
* * * * *
Dated: January 25, 2022.
For the Nuclear Regulatory Commission.
Andrea D. Veil,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 2022-04374 Filed 3-2-22; 8:45 am]
BILLING CODE 7590-01-P